In the steel fabrication industry, it is often necessary to cut structural steel members, such as I-beams, channels, and the like to an accurate predetermined length from an elongate piece of stock. One known commercially available system for performing this operation includes a powered roller conveyor adapted to receive the elongate stock and a remotely adjustable movable stop unit adapted to be positioned at selected adjusted locations alongside the conveyor. The stop unit includes an hydraulic assembly which releasably grips the track on which the unit rides and an abutment plate which can be moved into and out of engagement with the end of the elongate stock, as desired. The movable unit has its own drive which permits it to be positioned at various selected locations along the length of the conveyor as determined by the operator. A scale extends alongside the conveyor. A TV camera in the movable unit reads the scale, and a monitor displays the reading at the work station.
In use, the stop unit is driven to a predetermined location with respect to the conveyor and is clamped to its guide track at that location. The stop plate is moved into the path of movement of the end of the elongate stock, and the stock is advanced lengthwise on the conveyor. When the end of the stock reaches the abutment plate, it is properly positioned at a predetermined location with respect to the work station, thereby enabling an operation, such as a cutting operation, to be performed on the stock at the work station. After the operation is performed, the abutment plate is displaced out of the path of movement of the cut stock, and the cut member is advanced lengthwise away from the work station by the power conveyor. Such apparatus is disclosed in U.S. Pat. No. 3,841,462.
While the aforedescribed system may function satisfactorily for its intended purpose, it has certain limitations. For one thing, it is complex and expensive. For another, the operator must exercise care so as not to engage the abutment plate with too great a force and thereby dislodge the stop unit inadvertently. Moreover, because the movable unit includes its own clamping and driving mechanism, it is not as inexpensive to maintain and operate as desired.
There are several other patented systems for measuring and cutting elongate stock to length. Such systems are disclosed in the following U.S. Pat. Nos: 2,619,134; 3,718,061; 3,811,196; 3,917,078; and 3,923,157. While these patented systems may function satisfactorily for their intended purposes, there is not currently commercially available a simple, reliable, easy to install, use and maintain system for enabling structural steel members to be cut accurately to length.